Glass boilers, boiling vessels, and the like are used in virtually all chemical laboratories because of their excellent chemical resistance and transparency. Stainless steel vessels are also used, but are limited because of their poor resistance to some acids and other chemicals. Glass boilers are generally interconnected to condensers, columns, receivers, and other glassware. Connections are made through standard joints known as interchangeable taper-ground joints, or standard taper joints (S.T.). Spherical joints are used to a lesser extent or can be connected to standard taper joints by means of adapters. Glass boiling vessels are generally the most vulnerable component of the boiler system, being sensitive to scratches, nicks, and other defects which act as stress raisers resulting in catastrophic failure at the slightest impact. Glass vessels generally boil liquids in a non-uniform manner, frequently with superheating and bumping.
A variety of plastic materials, particularly the fluoroplastics, are also highly resistant to most chemicals, even more so than borosilicate glass. Some are transparent or translucent, and resistant to breakage. However, plastic materials have low thermal conductivity, about 1/4 to 1/6 that of glass and, therefore, are poorly suited for making boilers or boiling flasks. However, fluoroplastic (polytetrafluoroethylene) boilers and boiling flasks are available with rounded bottoms suitable for use with heating mantles. Some of the boilers have molded on PTFE joints for connections to PTFE receivers and other PTFE laboratory ware. Such vessels heat very slowly because of the low thermal conductivity of the plastic. These PTFE vessels are opaque.
It is, therefore, apparent that there has existed for a long time a need for an efficient transparent or translucent plastic boiler that brings liquids to a rapid, uniform and smooth boil, free of bumping. One that connects to virtually any glass system, is chemically resistant, a kilowatt saver, and adds a big safety factor--being shatter and impact resistant.